The present invention relates to a rail profile grinding machine intended for new work and for maintenance work on railroad tracks and similar runways, particularly in the field of rail transport, mining and handling.
A rail profile grinding machine is a machine designed to grind the head of a rail, mainly after it has been welded to form a track, with a view to giving the weld region a profile identical to the profile of the running part of the rail. Usually, rail profile grinding operations affect both the top face of the rail and the two flanks of the rail head, these flanks facing respectively toward the inside and toward the outside of the track.
More specifically, the invention is aimed at improving a rail profile grinding machine of the type comprising a grinding head carrying an abrasive grinding tool mounted to rotate about an axis and capable also of describing an up/down movement parallel to its axis of rotation, the grinding head being carried by a chassis provided, at its ends, with means for running, guiding and fitting on a rail of a railroad track or the like, the grinding machine also comprising motorized means for rotating the grinding tool about its axis and maneuvering means for moving the grinding machine back and forth in the longitudinal direction of the rail that is to be ground, the chassis pivoting with the grinding head about a longitudinal axis so as to provide a choice of grinding the top side of the rail, or the flank of the rail head on the inside of the track or the flank of the rail head on the outside of the track.
In a machine such as this, the chassis and the grinding head carried by the chassis can be inclined at will to one side of the rail or the other, starting from a substantially vertical starting position, so as to allow the top face of the rail or the flanks of the rail head to be ground.
As far as the motorized means for rotating the grinding tool are concerned, certain grinding machines use an internal combustion engine which in itself constitutes a beneficial solution because grinding machines are usually used out of doors where no source of electrical or hydraulic energy is available. Recourse to a combustion engine does, however, pose its own problems, for grinding machines of the kind concerned here.
Hence, in a grinding machine of this kind, produced previously by the applicant, and marketed under the name xe2x80x9cMP 12xe2x80x9d, the combustion engine is carried directly by the chassis, the output shaft of the engine being parallel to the axis of rotation of the grinding tool. What this means is that this engine is inclined with the chassis and the grinding head when these parts are used in an inclined position. Now, the operation of an internal combustion engine is thrown into jeopardy by excessive inclination, which in particular poses problems of carburation and lubrication and may lead to reduced engine life,
In another known embodiment described in German patent application No. 19518457, the internal combustion engine is carried by the maneuvering arm of the grinding machine, kept in a vertical plane, and not carried by the chassis of the grinding machine, which means that this engine remains more or less upright, even if the chassis is inclined. However, such an embodiment entails, between the output shaft of the combustion engine and the grinding tool, a complex transmission which is not very reliable and is rather expensive, and which, in the embodiment according to the aforementioned German patent application, comprises, in succession: a flexible shaft, an angle transmission involving bevel gears, a universal joint and a belt.
The present invention sets out to avoid all these drawbacks by providing a simple and reliable solution to transmitting movement between the combustion engine and the grinding tool, while at the same time limiting the inclination of this engine to small angles, guaranteeing correct operation and longevity of said engine.
Another objective of the invention is to provide a rail profile grinding machine that gives the operator a more ergonomic and less tiring working position
To this end, the subject of the invention is essentially a rail profile grinding machine of the kind indicated in the introduction, in which the motorized means for rotating the grinding tool consist of an internal combustion engine with horizontal output shaft, the engine being fixed to a support which is articulated, about a longitudinal axis, to a balancing assembly itself mounted to pivot about a longitudinal spindle on the chassis and designed to occupy, in use, a horizontal position resting on the other rail of the track, while the horizontal output shaft of the engine is connected, via a transmission assembly, to the grinding head carried by the chassis in such a way as to limit the inclination of the engine to small angles.
Thus, the invention proposes a special mounting of the combustion engine, this engine being fixed to a support mounted to pivot, about a horizontal axis, on a balancing assembly itself occupying a position which is invariably horizontal when the grinding machine is in use. The engine is also connected to the chassis via the transmission assembly which, in a preferred embodiment of the invention, comprises a transmission box forming a kind of link, articulated between the output shaft of the engine and a horizontal axis embodied by a spindle connected to the chassis or to the grinding head. Thus, the combustion engine is mounted via an articulated device forming a kind of deformable quadrilateral which is such that the inclination of the pivoting support of the engine, and therefore of the engine itself, with respect to the horizontal remains small and in particular does not exceed about 15xc2x0, whereas the chassis carrying the grinding head can be inclined by xc2x1900xc2x0 to one side or the other with respect to its vertical central position.
Advantageously, spring-loaded means are provided, which act on the pivoting support of the combustion engine to compensate for the weight of this engine. These spring-loaded means, which lighten the load to be exerted by the operator, can be produced in the form of a gas spring or a spring of any other kind, articulated between the balancing assembly and the pivoting support of the engine.
In one embodiment of the invention, the transmission assembly comprises a driving gear wheel carried by the horizontal output shaft of the engine, a toothed belt housed in the transmission box, a receiving gear wheel fixed on the horizontal shaft mounted to rotate about the horizontal axis of articulation of the transmission box to the chassis or the grinding head, and an angular transmission in the form of a pair of bevel gears connecting the latter shaft to a sleeve coaxial with the grinding tool and connected by splines to a shaft carrying the grinding tool.
This then yields a transmission assembly which is simple, lightweight and protected, requires no maintenance and is reliable. Advantageously, in order to input the movement conveniently into the grinding head, the chassis has two offset longitudinal portions, the horizontal shaft mounted along the axis of articulation of the transmission box entering the grinding head at the discontinuity between the two portions of the chassis.
According to another feature, the balancing assembly comprises, on the one hand, a bow connecting the ends of the chassis together and pivoting via its own ends about a longitudinal spindle, relative to this chassis, and, on the other hand, a transverse balancing bar fixed removably to the central part of the bow and provided with a roller or follower designed to press and roll along the other rail of the track. The pivoting support of the engine may be articulated to a yoke, it too fixed in the central part of the bow, some distance from the axis of articulation of the bow on the chassis.
According to yet another feature, given the fact that the chassis of the grinding machine that is the subject of the invention can be inclined by xc2x190xc2x0 to one side or the other with respect to its vertical central position, the maneuvering means for the back and forth movement of the grinding machine advantageously comprise an orientable maneuvering arm mounted to pivot about a longitudinal axis on the chassis, means being provided for immobilizing the maneuvering arm in a preselected angular position. The maneuvering arm can thus be oriented by xc2x145xc2x0 to each side of a central position, to maintain an ergonomic position of use even if the chassis, which carries this maneuvering arm, is lying down horizontal.
According to a last feature, the chassis of the grinding machine that is the subject of the invention carries, at each end, a set of two guide rollers with parallel axes, mounted on a cowman support itself mounted to rotate about a longitudinal axis relative to the corresponding end of the chassis, on which end is also pivotably mounted one end of the balancing assembly, a connection by way of gears connecting the support of the guide rollers to the end of the balancing assembly and/or to the chassis in such a way that pivoting of this assembly relative to the chassis is accompanied by proportional orientation of the guide rollers. The inclination of the chassis and of the grinding head is thus accompanied by an xe2x80x9cautomaticxe2x80x9d orientating of the guide rollers, which adopt a suitable position depending on whether it is the inside flank or the outside flank of the rail head that is being ground